A recorded or recordable recording medium such as a compact disc (CD) and a digital versatile disc (DVD) and the like have been considered to record identification information (ID) peculiar to a recording medium thereon as medium information. This record of the medium information allows the medium information to be used as an identifier for deciding whether this recording medium is an authentic one or an illegally copied one.
Besides using the medium information as the identifier of recording medium, it is conceivable that a part of this medium information can be used as an identifier to acquire a particular service information (contents for service such as music, movie, and software) by accessing a particular service institution. If so, it is possible to utilize the medium information as means for a campaign to purchase a recording medium because providing the user who would purchase the recording medium with the particular service information causes his or her purchasing inclination to be fueled.
As the medium information, information available for utilization in any other ways (hereinafter referred to as “relevant information”) can be added besides medium identification information for identifying the recording medium itself. Using the added relevant information, it is realized that a variety of services peculiar to the recording medium that is different from the above can be provided.
If the various services, for example, information recorded on a recording medium have been encrypted, it is possible that key information required for decryption of the information is acquired from an administrative server, which administers medium information. This is because, also in a case where information is to be recorded on a recording medium as encrypted, if key information (decryption key etc.) for decryption of the information is recorded on the same recording medium, the encrypted information can be decrypted using the key information recorded in the recording medium itself when the recording medium is illegally copied. Storing the key information separately from the recording medium allows such illegal utilization thereof to be eliminated.
Alternatively, if information indicating a classification of a recording medium is recorded as the relevant information, the information indicating the classification may be doubly used as information for identifying the medium together with the medium identification information. This allows an illegally copied recording medium to be eliminated effectively and certainly. According to this, protection of copyright on the information recorded on the recording medium may be realized.
If this relevant information is available, it is further possible to acquire information (contents) related to information recorded or to be recorded, that is, music information, information about artists etc. related to the music information, image information (still images, moving images), or digital information such as program data, which is used in a computer, on the circumstances.
As subjected recording medium, in addition to a write-once recording medium such as CD-Recordable (CD-R) and a rewritable recording medium such as CD-Rewritable (CD-RW), a reproduction-only recording medium such as CD-ROM disc and DVD-ROM disc where information is recorded as a plurality of pits having multiple irregular patterns beforehand, semiconductor memory, and the like are illustrated.
However, medium information recorded on the recording medium has been used for identifying the recording medium itself, and thus, it is necessary to make at least the medium identification information invisible from a user in the terms of security (as secret information). On the other hand, this medium information may be ranked at one function of an identifier required to enjoy the various services. If so, it would be preferable to make the medium information accessible from the user beforehand, i.e. visible therefrom.